Modern applications of semiconductor packages have an increasing demand for quick improvements in performance of their electric components and circuits. To keep up with the raising demand of better performance, higher power density, more efficiency, lower cost and space, more integration, higher functionality, increased digital content, etc., the silicon process technologies undergo continuous improvement steps. Correspondingly the technology development cycles of entire silicon process platforms have shrunk dramatically, sometimes with intermediate process upgrades on a yearly time base.
Consequently the market and the applications can take advantage of newer and better performing devices on shorter and shorter time scales. Existing products will be replaced by a next generation part with faster turn-around cycles than ever before. The quick adoption of a better performing silicon (or other semiconductor materials) process technology is advantageous to improve systems like electronic control units as quickly as possible.
On the other hand this quick replacement of existing parts by newer devices can also cause many problems for the system and circuit designs using those parts. Since the design-in of a newer or better performing devices normally requires changes or modifications of the circuit layout or the main system, such as an electronic control unit, unless the new part offers exactly the same layout, package, pin count, electric supply requirements, protective circuits, and the like.
Therefore, it is advantageous to produce a pin-compatible replacement product which provides a better performance (e.g. better electric behavior, higher power, etc.) while the user-application need not be changed. Thus, a printed circuit copper board or the like doesn't need to change its trace layout if the replacement part is in the same package and has the same footprint and layout as the older version.
This is especially important for applications such as automotive applications which do not change hardware generations as frequently as the silicon process technology offers improved parts. If the newer silicon technology offers a better performing device in the same package and with a pin-compatible layout, the application (e.g. an Electronic Control Unit “ECU”) can use the newer product without expensive changes of the system design. In that case a re-qualification of the system with the new component is sufficient.
Therefore, in many applications, especially automotive applications, it is preferred to implement a better performing part without sacrificing the existing system layout such as a printed circuit board (PCB). For this purpose it is a major market advantage and of great customer value to generate quasi-identical, pin-compatible replacement parts.
Unfortunately, even if pin-compatibility can be achieved, newer silicon or GaN technology might have different electric characteristics that require changes of the system circuitry even if the package outline and the footprint of the replacement part are identical to the predecessor package. Often the demand for higher integration and more functionality drives a newer silicon generation (especially IC circuits). Therefore, the newer silicon IC generations often implement more logic capabilities (e.g. CMOS logic, digital content, microcontroller capability, memory cells, etc.) which can turn a formerly very rugged and robust IC-process with less “smartness” into a more capable but less rugged device.
Thus, when converting IC or other devices to a more logic capable and higher integrated process, while some functions and parameters are more rugged than in the older process there are also some elements in the new designs that require additional protection or safety features. In such a case a customer who replaces a pin compatible part with a newer part still needs to redesign the application circuit and implement external protecting pre-resistors or other devices or circuits to limit certain current or voltage inputs.
With the need for those additional changes the advantage of a theoretically “pin-compatible” replacement part can be drastically reduced. In some cases a user might even be very reluctant to use it due to the need for additional changes in his system circuitry. In such a case a beneficial drop-in replacement of a newer part will be delayed until the application undergoes a re-design into a newer generation that can add the external protection elements for the newer part. In the automotive market, for example, this generation change is typically linked to car model design cycles which change typically every 3-5 years. This is a major drawback for the quick adaptation of replacement parts with newer silicon or other technology and better performance.
As previously stated, The required protection of sensitive sections or pins of an IC for example may be done with a pre-resistor (or other component) which is mounted externally on a PCB or other circuitry. Similarly, certain circuit blocks and contact pins of parts may need additional pre-resistors when used in the same application as the original part which did not need this resistor.
The disadvantages of this prior art solution are:
a) the user has to implement the changes on his system and carry the cost and time delay for changing the entire system such as a different PCB layout and changes in the assembly process to implement the pre-resistor or other component.
b) if the user is not aware of the need for a pre-resistor he might just replace the older generation part with the newer “pin-compatible” product and cause unaccepted failures in his application.
It would be very advantageous to implement the necessary new protection in a way that a new pin-compatible part does not need external protection.